- Create an all static TypedDataView class which uses implicit field offset

runtime/vm/class_finalizer.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/class_finalizer.h"
 
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/longjump.h"
@@ skipping 149 matching lines @@
     // Clear pending classes array.
     class_array = GrowableObjectArray::New();
     object_store->set_pending_classes(class_array);
   } else {
     retval = false;
   }
   isolate->set_long_jump_base(base);
   if (FLAG_use_cha) {
     RemoveOptimizedCode(added_subclasses_to_cids);
   }
+  VerifyImplicitFieldOffsets();
   return retval;
 }
 
 
 // Adds all interfaces of cls into 'collected'. Duplicate entries may occur.
 // No cycles are allowed.
 void ClassFinalizer::CollectInterfaces(const Class& cls,
                                        const GrowableObjectArray& collected) {
   const Array& interface_array = Array::Handle(cls.interfaces());
   AbstractType& interface = AbstractType::Handle();
@@ skipping 1786 matching lines @@
 
 void ClassFinalizer::ReportError(const char* format, ...) {
   va_list args;
   va_start(args, format);
   const Error& error = Error::Handle(
       Parser::FormatError(Script::Handle(), -1, "Error", format, args));
   va_end(args);
   ReportError(error);
 }
 
+
+void ClassFinalizer::VerifyImplicitFieldOffsets() {
+#ifdef DEBUG
+  const ClassTable& class_table = *(Isolate::Current()->class_table());
+  Class& cls = Class::Handle();
+  Array& fields_array = Array::Handle();
+  Field& field = Field::Handle();
+
+  // First verify field offsets of all the TypedDataView classes.
+  for (intptr_t cid = kTypedDataInt8ArrayViewCid;
+       cid <= kTypedDataFloat32x4ArrayViewCid;
+       cid++) {
+    cls = class_table.At(cid);  // Get the TypedDataView class.
+    cls = cls.SuperClass();  // Get it's super class '_TypedListView'.
+    fields_array ^= cls.fields();
+    ASSERT(fields_array.Length() == TypedDataView::NumberOfFields());
+    field ^= fields_array.At(0);
+    ASSERT(field.Offset() == TypedDataView::data_offset());

[Ivan Posva, 2013/04/05 04:23:55]

You probably also want to check the name of the field, otherwise this test does
not make a lot of sense. The first field in the list should always have the
offset of 2 * wordSize.

+    field ^= fields_array.At(1);
+    ASSERT(field.Offset() == TypedDataView::offset_in_bytes_offset());
+    field ^= fields_array.At(2);
+    ASSERT(field.Offset() == TypedDataView::length_offset());
+  }
+
+  // Now verify field offsets of '_ByteDataView' class.
+  cls = class_table.At(kByteDataViewCid);
+  fields_array ^= cls.fields();
+  ASSERT(fields_array.Length() == TypedDataView::NumberOfFields());
+  field ^= fields_array.At(0);
+  ASSERT(field.Offset() == TypedDataView::data_offset());
+  field ^= fields_array.At(1);
+  ASSERT(field.Offset() == TypedDataView::offset_in_bytes_offset());
+  field ^= fields_array.At(2);
+  ASSERT(field.Offset() == TypedDataView::length_offset());
+
+#endif
+}
+
 }  // namespace dart